<p>Understanding the rock instability problems in the mountainous terrain is crucial for life safety and long-term stability of rock engineering structures. These problems become more vulnerable when the rock masses have a weathered anisotropic nature and are encountered with cyclic loading activities. The mechanical response of rock masses depends on the properties of intact rock and discontinuities. The rocks fail at lower stress levels under cyclic loading than their uniaxial compressive strength. The strength of the foliated rocks depends on the angle between the inherent foliations and the major principal loading axis direction. Also, the progressive weathering decreases the rock strength. The stability of rock masses mainly depends on the shear strength of joints. The shear strength of joints is estimated using the Barton (Eng Geol 7(4):287-332, 1973) criterion. This criterion does not include the combined influence of weathering, anisotropic foliations, and cyclic loading response. The present article introduces a novel framework to integrate the combined influence of weathering, anisotropy, and cyclic loading response on Barton’s peak friction angle (<InlineEquation ID="IEq1"> <EquationSource Format="TEX">$\phi_{Barton}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>ϕ</mi> <mrow> <mi mathvariant="italic">Barton</mi> </mrow> </msub> </math></EquationSource> </InlineEquation>). The increasing weathering grades, varying anisotropy angles, and cyclic loading interaction lead to the attenuation of joint wall compressive strength (JCS) and residual friction angle (<InlineEquation ID="IEq2"> <EquationSource Format="TEX">$\phi_{r}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>ϕ</mi> <mi>r</mi> </msub> </math></EquationSource> </InlineEquation>) that ultimately causes the decrease in <InlineEquation ID="IEq3"> <EquationSource Format="TEX">$\phi_{Barton}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>ϕ</mi> <mrow> <mi mathvariant="italic">Barton</mi> </mrow> </msub> </math></EquationSource> </InlineEquation> values. The study also investigates the variations of <InlineEquation ID="IEq4"> <EquationSource Format="TEX">$\phi_{Barton}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>ϕ</mi> <mrow> <mi mathvariant="italic">Barton</mi> </mrow> </msub> </math></EquationSource> </InlineEquation> with joint roughness coefficient (JRC) values, fatigue life, and normal stresses for three weathering grades (fresh, slightly, and moderately weathered) of Himachal gneiss at five anisotropy angles (0°, 30°, 45°, 60°, and 90°). This approach helps to link the shear strength of joints with the cyclic strength of intact rocks that significantly varies with the anisotropy angle and reduces with the increasing weathering grades. This research helps in integrating fatigue life of rocks with joint shear strength, carrying the significant implications in landslides and rockfall hazards assessment.</p>

The Combined Influence of Weathering, Anisotropy, and Cyclic Loading on Barton’s Peak Friction Angle: Scaling Intact Rock Behaviour to Rock Joint

期刊论文
发表日期：

2026年5月21日

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Honey Kaushal,
Aditya Singh,
Narendra Kumar Samadhiya

摘要

Understanding the rock instability problems in the mountainous terrain is crucial for life safety and long-term stability of rock engineering structures. These problems become more vulnerable when the rock masses have a weathered anisotropic nature and are encountered with cyclic loading activities. The mechanical response of rock masses depends on the properties of intact rock and discontinuities. The rocks fail at lower stress levels under cyclic loading than their uniaxial compressive strength. The strength of the foliated rocks depends on the angle between the inherent foliations and the major principal loading axis direction. Also, the progressive weathering decreases the rock strength. The stability of rock masses mainly depends on the shear strength of joints. The shear strength of joints is estimated using the Barton (Eng Geol 7(4):287-332, 1973) criterion. This criterion does not include the combined influence of weathering, anisotropic foliations, and cyclic loading response. The present article introduces a novel framework to integrate the combined influence of weathering, anisotropy, and cyclic loading response on Barton’s peak friction angle ( $\phi_{Barton}$ $ϕ_{Barton}$ ). The increasing weathering grades, varying anisotropy angles, and cyclic loading interaction lead to the attenuation of joint wall compressive strength (JCS) and residual friction angle ( $\phi_{r}$ $ϕ_{r}$ ) that ultimately causes the decrease in $\phi_{Barton}$ $ϕ_{Barton}$ values. The study also investigates the variations of $\phi_{Barton}$ $ϕ_{Barton}$ with joint roughness coefficient (JRC) values, fatigue life, and normal stresses for three weathering grades (fresh, slightly, and moderately weathered) of Himachal gneiss at five anisotropy angles (0°, 30°, 45°, 60°, and 90°). This approach helps to link the shear strength of joints with the cyclic strength of intact rocks that significantly varies with the anisotropy angle and reduces with the increasing weathering grades. This research helps in integrating fatigue life of rocks with joint shear strength, carrying the significant implications in landslides and rockfall hazards assessment.